CN102822537B - Hybrid working machine - Google Patents

Abstract

The controller judges whether the operation valve that controls the supply of pressure fluid from the main pump to the actuator is in the neutral position, detects the input power of the hydraulic motor that is rotated by the return oil from the actuator, and the operation valve is in the neutral position. position and the input power of the hydraulic motor exceeds the first threshold value, the opening degree of the proportional electromagnetic throttle valve is reduced.

Description

Hybrid Work Machinery

technical field

The present invention relates to a hybrid work machine utilizing regenerative flow from an actuator.

Background technique

JP2009-236190A discloses a hybrid work machine utilizing regenerative flow rate of an actuator. In this hybrid work machine, an on-off valve is provided between a boom cylinder as an actuator and a hydraulic motor for regeneration. With the operating valve controlling the actuator returning to the neutral position, the on-off valve maintains the closed position.

In the case of an emergency stop of the boom cylinder operating at high speed with a high load, the operation valve is switched to the neutral position and the on-off valve is switched to the closed position at the same time to prevent the boom cylinder from running out of control and avoid the motor generator High torque above the absorbing capacity is input from the hydraulic motor to the motor generator. Accordingly, it is prevented that a high torque exceeding the absorbing capacity of the motor generator acts on the motor generator, causing the motor generator to malfunction or run out of control.

Contents of the invention

However, in the above-mentioned conventional hybrid working machine, when the operation valve is returned to the neutral position abruptly in order to stop the actuator in an emergency, a high torque exceeding the absorption capacity of the motor generator may act on the motor generator. machine. This is because there is a limit to the responsiveness of the on-off valve, and it is difficult to instantaneously close the on-off valve to stop the actuator in an emergency.

In order to increase the absorption capacity of the motor generator, it is considered to increase the size of the motor generator, but the cost increases accordingly.

The object of the present invention is to reliably stop the actuator and avoid the action of high torque exceeding the absorbing capacity when the actuator in the high-speed operation with a high load is suddenly stopped in the case of a hybrid power working machine. in motor generators.

According to one aspect of the present invention, there is provided a hybrid working machine including: a main pump; an engine driving the main pump; a variable capacity auxiliary pump connected to a discharge side of the main pump via a confluence passage; an inclination controller that controls the deflection angle of the above-mentioned auxiliary pump; a proportional electromagnetic throttle valve that is provided on the above-mentioned confluence path; an actuator; an operation valve that controls the supply of pressurized fluid from the above-mentioned main pump to the above-mentioned actuator ; a variable capacity hydraulic motor, which is rotated using return oil from the above-mentioned actuator; a motor generator, which is connected to the above-mentioned auxiliary pump and the above-mentioned hydraulic motor; a battery, which is connected to the above-mentioned motor generator; The device is connected to the above-mentioned inclination controller and the above-mentioned proportional electromagnetic throttle valve, judges whether the above-mentioned operation valve is in the neutral position, and detects the input power of the above-mentioned hydraulic motor that is rotated by the return oil from the above-mentioned actuator. When the valve is in the neutral position and the input power of the hydraulic motor exceeds a first threshold value, the opening degree of the proportional electromagnetic throttle valve is reduced.

According to the above aspect, when the input power of the hydraulic motor exceeds the first threshold value, the auxiliary pump absorbs the input power of the hydraulic motor, so that the input of power exceeding the absorbing capacity to the motor generator can be prevented.

Therefore, even if the responsiveness of the on-off valve is not improved or the motor generator is not enlarged beyond the necessary level, the absorption capacity will not be reduced when the actuator in high-speed operation with a high load is suddenly stopped. The above high torque acts on the motor generator to reliably stop the actuator.

Hereinafter, embodiments of the present invention and advantages of the present invention will be described in detail with reference to the drawings.

Description of drawings

FIG. 1 is a circuit diagram of a power shovel according to an embodiment of the present invention.

FIG. 2 is a flowchart showing a first control flow.

FIG. 3 is a flowchart showing a second control flow.

Detailed ways

FIG. 1 is a circuit diagram of an excavator according to an embodiment of the present invention. The excavator is provided with variable-capacity first and second main pumps MP1 and MP2. The first main pump MP1 is connected to the first circuit system. The second main pump MP2 is connected to the second loop system.

In the first circuit system, connected in order from the upstream side are: the operation valve 1 for controlling the swing motor RM, the operation valve 2 for controlling the first gear of the arm cylinder, and the actuator for controlling the arm cylinder BC. The operating valve 3 for arm 2, the operating valve 4 for controlling the spare parts, and the operating valve 5 for controlling the motor for left travel.

The operating valves 1 to 5 are connected to the first main pump MP1 through the neutral flow path 6 and the parallel path 7 , respectively.

A pilot pressure (pilot pressure) generating mechanism 8 is provided on the downstream side of the operation valve 5 on the neutral flow path 6 . The pilot pressure generating mechanism 8 generates a high pilot pressure when the flow rate flowing through the pilot pressure generating mechanism 8 is large, and generates a low pilot pressure when the flow rate is small.

The neutral flow path 6 guides all or a part of the fluid discharged from the first main pump MP1 to the tank T when all the operation valves 1 to 5 are at or near the neutral position. In this case, the flow rate passing through the pilot pressure generating mechanism 8 also increases, so a high pilot pressure is generated.

If the operating valves 1 to 5 are switched to a full stroke state, the neutral flow path 6 is closed and the flow of fluid is stopped. In this case, the flow through the pilot pressure generating mechanism 8 almost disappears, and the pilot pressure remains at zero.

Here, according to the operation amount of the operation valves 1 to 5, part of the pump discharge is directed to the actuator and part of the pump discharge is directed to the tank T from the neutral flow path 6, so the pilot pressure generating mechanism 8 generates a flow rate corresponding to the flow rate flowing through the neutral flow path 6. pilot pressure. That is, the pilot pressure generating mechanism 8 generates pilot pressures corresponding to the operation amounts of the operation valves 1 to 5 .

A pilot flow path 9 is connected to the pilot pressure generating mechanism 8 . The pilot flow path 9 is connected to a regulator 10 that controls the deflection angle of the first main pump MP1. The regulator 10 controls the discharge amount of the first main pump MP1 inversely proportional to the pilot pressure. Therefore, when the operation valves 1 to 5 are at full stroke and the flow in the neutral flow path 6 becomes zero, in other words, when the pilot pressure generated by the pilot pressure generating mechanism 8 becomes zero, the first main The discharge of pump MP1 is kept at a maximum.

A first pressure sensor 11 is connected to the pilot flow path 9 . The pressure signal of the first pressure sensor 11 is input to the controller C.

In the second circuit system, the operation valve 12 for controlling the right travel motor, the operation valve 13 for controlling the bucket cylinder, and the first gear for controlling the boom cylinder BC are connected in order from the upstream side. The operation valve 14 and the operation valve 15 for controlling the second gear of the arm of the arm cylinder. The operation valve 14 is provided with a sensor 14a for detecting the operation direction and the operation amount.

The operation valves 12 to 15 are connected to the second main pump MP2 via the neutral flow path 16 . The operation valve 13 and the operation valve 14 are connected to the second main pump MP2 via a parallel passage 17 .

A pilot pressure generating mechanism 18 is provided on the neutral flow path 16 downstream of the operation valve 15 . The pilot pressure generating mechanism 18 functions exactly the same as the pilot pressure generating mechanism 8 described above.

A pilot flow path 19 is connected to the pilot pressure generating mechanism 18 . The pilot flow path 19 is connected to a regulator 20 that controls the deflection angle of the second main pump MP2. The regulator 20 controls the discharge amount of the second main pump MP2 inversely proportional to the pilot pressure. When the operation valves 12 to 15 are at full stroke and the flow in the neutral flow path 16 becomes zero, in other words, when the pilot pressure generated by the pilot pressure generating mechanism 18 becomes zero, the second main pump MP2 The output volume is kept at the maximum.

A second pressure sensor 21 is connected to the pilot flow path 19 . The pressure signal of the second pressure sensor 21 is input to the controller C.

The first and second main pumps MP1 and MP2 are coaxially rotated by the driving force of one engine E.

The engine E is provided with a generator (generator) 22 . The generator 22 uses the surplus output of the engine E to rotate and generate electricity. The electric power generated by the generator 22 is charged into the battery 24 through the battery charger 23 .

The battery charger 23 can charge the battery 24 with electric power even when it is connected to a general household power supply 25 . That is, the battery charger 23 can also be connected to other independent system power sources.

Passages 26 and 27 communicating with the swing motor RM are connected to the actuator port of the operation valve 1 connected to the first circuit system. Brake valves 28 , 29 are respectively connected to the two passages 26 , 27 . When the operation valve 1 is kept at the neutral position, the actuator port is closed, and the turning motor RM remains in a stopped state.

When the operation valve 1 is switched to a certain path, pressure fluid is supplied from a certain path, for example, the path 26 to rotate the rotary motor RM. Return fluid from swing motor RM returns to tank T through passage 27 .

When the swing motor RM is being driven, the brake valve 28 or 29 functions as a relief valve, and when the pressure in the passages 26 and 27 is higher than the set pressure, the brake valves 28 and 29 are opened to release the pressure on the high pressure side. Fluid is directed to the low pressure side.

If the operation valve 1 is returned to the neutral position in a state where the swing motor RM is rotating, the actuator port of the operation valve 1 is closed. Even if the actuator port operating the valve 1 is closed, the rotary motor RM continues to rotate by using inertial energy, and by rotating by using inertial energy, the rotary motor RM acts as a pump. In this case, a closed circuit is formed by the passages 26 , 27 , the rotary motor RM, and the brake valve 28 or 29 , and the inertial energy is converted into thermal energy through the brake valve 28 or 29 .

On the other hand, when the operation valve 14 is switched from the neutral position to the right position in the drawing, the pressurized fluid from the second main pump MP2 is supplied to the piston-side chamber 31 of the boom cylinder BC via the passage 30 . The return fluid from the rod side chamber 32 returns to the tank T through the passage 33, and the boom cylinder BC expands.

When the operation valve 14 is switched to the left direction in the drawing, the pressurized fluid from the second main pump MP2 is supplied to the rod side chamber 32 of the boom cylinder BC through the passage 33 . The return fluid from the piston-side chamber 31 returns to the tank T via the passage 30, and the boom cylinder BC contracts. The operation valve 3 is switched in conjunction with the operation valve 14 .

A proportional solenoid valve 34 whose opening degree is controlled by a controller C is provided in a passage 30 connecting the piston-side chamber 31 of the boom cylinder BC and the operation valve 14 . The proportional solenoid valve 34 maintains a fully open position under normal conditions.

Next, the variable displacement auxiliary pump AP that assists the outputs of the first main pumps MP1 and MP2 will be described.

Auxiliary pump AP is rotated by driving force from motor generator MG. A variable capacity hydraulic motor AM is also coaxially rotated by the driving force of the motor generator MG. An inverter I is connected to the motor generator MG. The inverter I is connected to a controller C, and the controller C can control the rotation speed of the motor generator MG and the like.

The deflection angles of the auxiliary pump AP and the hydraulic motor AM are controlled by the inclination controllers 35 and 36 . The inclination controllers 35, 36 are controlled according to the output signal of the controller C.

A discharge passage 37 is connected to the auxiliary pump AP. The discharge passage 37 is branched into a first confluent passage 38 that merges with the discharge side of the first main pump MP1 and a second confluent passage 39 that merges with the discharge side of the second main pump MP2. First and second proportional electromagnetic throttle valves 40 and 41 whose openings are controlled according to the output signal of the controller C are provided on the first and second confluent passages 38 and 39 , respectively.

A connection passage 42 is connected to the hydraulic motor AM. The connection passage 42 is connected to the passages 26 and 27 connected to the rotary motor RM via a confluence passage 43 and check valves (check valves) 44 and 45 . An electromagnetic on-off valve 46 whose opening and closing is controlled by a controller C is provided in the confluent passage 43 . A pressure sensor 47 is provided between the electromagnetic on-off valve 46 and the check valves 44 , 45 , and the pressure sensor 47 detects the pressure during rotation or braking of the swing motor RM. A pressure signal from the pressure sensor 47 is input to the controller C.

A relief valve 48 is provided in the confluent passage 43 at a position downstream of the electromagnetic on-off valve 46 with respect to the flow from the swing motor RM to the connection passage 42 . For example, when a failure occurs in the electromagnetic on-off valve 46 or the like, the safety valve 48 maintains the pressures of the passages 26 and 27 to prevent runaway of the swing motor RM.

A passage 49 communicating with the connection passage 42 is provided between the boom cylinder BC and the proportional solenoid valve 34 . An electromagnetic on-off valve 50 controlled by a controller C is provided in the passage 49 .

Next, the operation of this embodiment will be described.

When the operating valve 1 is switched to the neutral position during the rotation of the rotary motor RM, a closed circuit is formed between the passages 26 and 27, and the brake valve 28 or 29 maintains the brake pressure of the closed circuit and converts the inertial energy into heat energy .

The pressure sensor 47 detects swing pressure or brake pressure. The pressure signal is input to controller C. The controller C switches the electromagnetic on-off valve 46 when detecting a pressure lower than the set pressure of the brake valves 28 and 29 within a range that does not affect the rotation of the swing motor RM or the braking operation. When the electromagnetic on-off valve 46 is switched, the pressure fluid guided to the rotary motor RM flows through the confluence passage 43 and is supplied to the hydraulic motor AM via the safety valve 48 and the connection passage 42 .

As will be described below, the controller C controls the deflection angle of the hydraulic motor AM based on the pressure signal from the pressure sensor 47 .

If the pressure in the passage 26 or 27 is not maintained at the pressure required for the turning operation or braking operation, the turning motor RM cannot be turned or braked.

Therefore, in order to maintain the pressure in the passage 26 or 27 as the swing pressure or the brake pressure, the controller C controls the deflection angle of the hydraulic motor AM and controls the load of the swing motor RM. Specifically, the controller C controls the deflection angle of the hydraulic motor AM so that the pressure detected by the pressure sensor 47 is substantially equal to the turning pressure or braking pressure of the turning motor RM.

When the hydraulic motor AM obtains a rotational force, the rotational force acts on the coaxially rotating motor generator MG. The rotational force of hydraulic motor AM acts as an assist force for motor generator MG. Therefore, it is possible to reduce the power consumption of the motor generator MG by an amount equivalent to the rotational force of the hydraulic motor AM.

The rotational force of the auxiliary pump AP can also be assisted by the rotational force of the hydraulic motor AM.

Next, a case where the boom cylinder BC is controlled by switching the operation valve 14 and the operation valve 3 linked thereto will be described.

When the operation valve 14 and the operation valve 3 linked thereto are switched to operate the boom cylinder BC, the operation direction and the operation amount of the operation valve 14 are detected by the sensor 14 a. The operation signal is input to the controller C.

Based on the operation signal of the sensor 14a, the controller C judges whether the operator intends to raise or lower the boom cylinder BC. If a signal for raising the boom cylinder BC is input to the controller C, the controller C keeps the proportional solenoid valve 34 in a normal state. In other words, the proportional solenoid valve 34 is kept at the fully open position. In this case, in order to ensure a predetermined discharge amount from the auxiliary pump AP, the controller C keeps the electromagnetic on-off valve 50 at the illustrated closed position, and controls the rotation speed of the motor generator MG and the deflection angle of the auxiliary pump AP. .

When the signal for lowering the boom cylinder BC is input from the sensor 14a to the controller C, the controller C calculates the lowering speed of the boom cylinder BC requested by the operator based on the operation amount of the operation valve 14, and closes the proportional solenoid valve. 34. Switch the electromagnetic on-off valve 50 to the open position.

When the proportional electromagnetic valve 34 is closed and the electromagnetic on-off valve 50 is switched to the open position, the entire amount of return fluid of the boom cylinder BC is supplied to the hydraulic motor AM. However, if the flow rate consumed by the oil motor AM is smaller than the flow rate required to maintain the operator-requested descending speed, the boom cylinder BC cannot maintain the operator-requested descending speed. In this case, the controller C controls the opening degree of the proportional solenoid valve 34 so that the flow rate consumed by the oil motor AM is The above flow is returned to tank T to maintain the lowering speed of boom cylinder BC as requested by the operator.

When fluid is supplied to hydraulic motor AM, hydraulic motor AM rotates. The rotational force of the hydraulic motor AM acts on the coaxially rotating motor generator MG. The rotational force of hydraulic motor AM acts as an assist force for motor generator MG. Therefore, power consumption can be reduced by an amount corresponding to the rotational force of the hydraulic motor AM.

In the case where the hydraulic motor AM is used as the drive source and the motor generator MG is used as the generator, the deflection angle of the auxiliary pump AP is set to zero to form an almost no-load state, and the hydraulic motor AM is maintained to be electrically powered. The output required for the rotation of the generator MG. Thereby, the motor generator MG can be made to perform the power generation function by utilizing the output of the hydraulic motor AM.

On the downstream side of the first and second proportional electromagnetic throttle valves 40 and 41, one-way valves 51 and 52 are provided. The one-way valves 51 and 52 allow only flow from the auxiliary pump AP to the first and second main pumps MP1 and MP2.

The controller C constantly monitors the magnitude of the input power (power on the inlet side) of the hydraulic motor AM. For example, the following three methods are considered for calculating the magnitude of power.

(1) A method of calculating using electric power generated by a motor generator, that is, current×voltage.

(2) A method of calculating the flow rate from the deflection angle of the hydraulic motor AM and the rotational speed of the motor generator MG, and multiplying the flow rate by the inlet pressure of the hydraulic motor AM.

(3) Mathematically model the dynamic characteristics of the hydraulic motor AM to estimate the deflection angle of the hydraulic motor AM, calculate the flow rate based on the deflection angle and the rotation speed of the motor generator MG, and multiply the flow rate by the inlet of the hydraulic motor AM pressure to calculate the method.

Any calculation method other than the above three calculation methods may also be used. Regardless of which method is used, the controller C monitors the input power of the oil hydraulic motor AM.

The controller C monitors the input power of the hydraulic motor AM, and checks whether all the operation valves 1-5, 12-15 maintain the neutral position based on the signals from the sensors provided on the operation valves 1-5, 12-15.

For example, when the boom cylinder BC is stopped, the operator returns the operation valves 3 and 14 to the neutral position. In this case, the controller C closes the electromagnetic on-off valve 50 according to the signal from the sensor.

In the case of an emergency stop of the boom cylinder BC, it is necessary to close the electromagnetic on-off valve 50 instantaneously while returning the operation valves 3 and 14 to the neutral position. However, there is a limit to the responsiveness of the electromagnetic on-off valve 50. A response delay occurs when valve 50 is closed.

When the boom cylinder BC operates with a high load, a large power at that time is input to the hydraulic motor AM when a response delay occurs in the electromagnetic on-off valve 50 . The controller C calculates the input power at this time, and judges whether the result of the calculation exceeds a preset first threshold ε1. Then, the controller C executes control corresponding to the flowchart shown in FIG. 2 according to the judgment result.

That is, when the hybrid control is started (step S1), the controller C judges whether or not all the operation valves 1~5, 12~15 are maintained at neutral positions (step S2). If one of the operating valves 1-5, 12-15 is in a switching position other than the neutral position, the controller C outputs the command signal required for normal hybrid control (step S3).

When all the operating valves 1-5, 12-15 maintain neutral positions, calculate the input power PL of the hydraulic motor AM (step S4), and determine whether the input power PL is greater than the first threshold ε1 (step S5).

If the input power PL is smaller than the first threshold ε1, it is determined that the emergency stop boom cylinder BC is not in the situation, and the controller C returns to step S3.

However, if the input power PL is greater than the first threshold value ε1, it is determined that the boom cylinder BC performing a high-load operation is urgently stopped, and the process proceeds to step S6.

In step S6, the controller C controls the deflection angle controller 35 of the auxiliary pump AP to increase the deflection angle of the auxiliary pump AP to increase the displacement per revolution. Furthermore, the controller C reduces the opening degrees of the first and second proportional electromagnetic throttle valves 40 and 41 . Therefore, the discharge amount per revolution is increased from the auxiliary pump AP, which passes through the first and second proportional electromagnetic throttle valves 40, 41, so the pressure loss increases, and the pressure loss amount is used as the braking force for the hydraulic motor AM. function.

Whether or not all the operation valves 1 to 5 and 12 to 15 are in the neutral position is judged in step S2 for the following reason. For example, when one of the operation valves is held at a switching position other than the neutral position, the actuator connected to the operation valve is operated, or the load of the actuator acts on the auxiliary pump AP. Therefore, even when the boom cylinder BC is suddenly stopped, the input power of the hydraulic motor AM can be absorbed by the load acting on the auxiliary pump AP. Therefore, only when all of the operation valves 1 to 5 and all of the operation valves 12 to 15 are in the neutral position, the control shown in step S6 is executed.

Therefore, for example, in the case of a crane (crane), only one operation valve for telescopic control is required, and therefore it is only necessary to determine whether or not the operation valve is in the neutral position.

In the above-mentioned embodiment, the control of the deflection angle of the auxiliary pump AP and the control of the opening degrees of the first and second proportional electromagnetic throttle valves 40 and 41 are performed simultaneously, but it is also possible to keep the deflection angle of the auxiliary pump AP at a certain value. To this extent, the opening degrees of the first and second proportional electromagnetic throttle valves 40 and 41 are controlled.

In step S5 shown in FIG. 2 , even if the input power PL of the hydraulic motor AM is smaller than the first threshold ε1, if the input power PL does not become sufficiently small after the lapse of time t1, it can be determined that the boom cylinder BC is in an abnormal state.

In this case, boom cylinder BC can be stopped reliably only by executing the control based on the flowchart shown in FIG. 3 .

In the control method shown in FIG. 3 , steps S1 to S6 are the same as those in FIG. 2 .

In step S5, even if the input power PL of the hydraulic motor AM is less than the first threshold ε1, the controller C judges in step S7 whether the input power PL becomes less than the second threshold ε2 after the preset time t1. The first threshold and the second threshold have a relationship of ε1>ε2.

If the input power PL becomes smaller than the second threshold ε2 in step S7, the controller C judges that the input power PL is sufficiently absorbed, returns to step S3, and performs normal hybrid control.

However, if the input power PL is greater than the second threshold ε2 in step S7, the controller C determines that the input power PL from the boom cylinder BC is not sufficiently absorbed and is in an abnormal state, and proceeds to step S8.

In step S8, the controller C controls the inclination controller 35 to maximize the deflection angle of the auxiliary pump AP to maximize the displacement per revolution. At the same time, the first and second proportional electromagnetic throttle valves 40 and 41 are closed.

As a result, the boom cylinder BC is reliably stopped, and the abnormal state is released.

In the above-mentioned embodiment, the regenerative power control of the boom cylinder BC has been described as an example, but the case of controlling the regenerative power of the swing motor RM is also the same as that of the boom cylinder BC.

That is, when the turning motor RM is stopped urgently, the operation valve 1 is returned to the neutral position, and the electromagnetic on-off valve 46 is closed. At this time, there is a limit to the responsiveness of the electromagnetic on-off valve 46 , so the input power of the hydraulic motor AM exceeds the absorbing capacity of the motor generator MG.

In this case, the controller C also performs control based on the flowcharts shown in FIGS. 2 and 3 .

As mentioned above, although embodiment of this invention was described, the said embodiment is only a part of the application example of this invention, and it does not mean that the technical scope of this invention is specifically limited to the said embodiment.

This application claims the priority based on Japanese Patent Application No. 2010-116604 for which it applied to Japan Patent Office on May 20, 2010, All the content of this application is incorporated in this specification by reference.

Industrial availability

The present invention can be utilized in hybrid working machines such as hybrid excavators.

Claims (3)

1. a hybrid working machine, possesses:

Main pump;

Motor, it drives above-mentioned main pump;

Variable-displacement service pump, it is connected to the discharge side of above-mentioned main pump via interflow path;

Pitch angle control device, it controls the angle of yaw of above-mentioned service pump;

Ratio electromagnetic throttle valve, it is arranged on the path of above-mentioned interflow;

Actuator;

Operating valve, it controls from above-mentioned main pump to the supply of the pressure fluid of above-mentioned actuator;

Variable-displacement hydraulic motor, it utilizes the oil that returns from above-mentioned actuator to rotate;

Motor generator set, it is connected to above-mentioned service pump and above-mentioned hydraulic motor;

Battery, it is connected to above-mentioned motor generator set; And

Controller, it is connected to above-mentioned pitch angle control device and aforementioned proportion electromagnetic throttle valve, judge whether aforesaid operations valve is in neutral position, detect the input power returning the above-mentioned hydraulic motor that oil carries out rotating utilized from above-mentioned actuator, when aforesaid operations valve is in neutral position and the input power of above-mentioned hydraulic motor exceedes first threshold, reduce the aperture of aforementioned proportion electromagnetic throttle valve.

2. hybrid working machine according to claim 1, is characterized in that,

When the input power of above-mentioned hydraulic motor exceedes above-mentioned first threshold, above-mentioned controller reduces the aperture of aforementioned proportion electromagnetic throttle valve, and controls above-mentioned pitch angle control device to increase the angle of yaw of above-mentioned service pump.

3. hybrid working machine according to claim 1, is characterized in that,

The power inputted to above-mentioned hydraulic motor after set time after the aperture reducing aforementioned proportion electromagnetic throttle valve exceedes the Second Threshold less than above-mentioned first threshold, above-mentioned controller controls above-mentioned pitch angle control device to make the angle of yaw of above-mentioned service pump maximum, and closes aforementioned proportion electromagnetic throttle valve.